Fix GCC warning in `ssl_calc_finished_tls_sha384`
This commit fixes the same warning fixed by baeedbf9, but without
wasting RAM. By casting `mbedtls_sha512_finish_ret()`, `padbuf`
could be kept 48 bytes long without triggering any warnings.
Signed-off-by: Rodrigo Dias Correa <rodrigo@correas.us>
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index ecb76de..d96dd8f 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -6363,13 +6363,16 @@
#endif /* MBEDTLS_SHA256_C */
#if defined(MBEDTLS_SHA512_C)
+
+typedef int (*finish_sha384_t)(mbedtls_sha512_context*, unsigned char[48]);
+
static void ssl_calc_finished_tls_sha384(
mbedtls_ssl_context *ssl, unsigned char *buf, int from )
{
int len = 12;
const char *sender;
mbedtls_sha512_context sha512;
- unsigned char padbuf[64];
+ unsigned char padbuf[48];
mbedtls_ssl_session *session = ssl->session_negotiate;
if( !session )
@@ -6396,7 +6399,13 @@
? "client finished"
: "server finished";
- mbedtls_sha512_finish_ret( &sha512, padbuf );
+ /*
+ * For SHA-384, we can save 16 bytes by keeping padbuf 48 bytes long.
+ * However, to avoid stringop-overflow warning in gcc, we have to cast
+ * mbedtls_sha512_finish_ret().
+ */
+ finish_sha384_t finish = (finish_sha384_t)mbedtls_sha512_finish_ret;
+ finish( &sha512, padbuf );
ssl->handshake->tls_prf( session->master, 48, sender,
padbuf, 48, buf, len );